Question
What is the proper way to administer the spontaneous, gaze right, gaze left and positional tests? Should tasking be used in the eyes closed portion? What directions should be used for the OPK test? What is considered an abnormal OPK?
Answer
Different people would give different answers to your first question. I perform the gaze test (called the ''spontaneous nystagmus test'' in the code book) by asking the patient to look 30 deg to the right, 30 deg to the left, 30 deg up, and 30 deg down with eyes open. Some people also test with the patient's eyes closed, but I find the results hard to interpret. Some people also test with the patient's eyes at center gaze, but I consider this to be part of the positional test. I perform the positional test (called ''the positional nystagmus test'' in the code book) with the patient in the sitting, supine, right-ear-down, and left-ear-down positions with eyes open at center gaze and eyes closed. Some people test in the right-side-down position instead of the right-ear-down position and in the left-side-down position instead of the left-ear-down position. I test in the right-side-down and/or left-side-down positions (to check for nystagmus induced by neck rotation) only if nystagmus is elicited by right-ear-down and/or left-ear-down positions. Some people also test in the head hanging position. I also perform the right and left Dix-Hallpike maneuver, and if the Dix-Hallpike maneuver elicits horizontal nystagmus, I perform the roll test to check for horizontal canal BPPV. Some people don't perform the Dix-Hallpike maneuver or the roll test.
Tasking should always be used when testing with the patient's eyes closed.
I don't give specific instructions for the OPK test at first, but if the patient doesn't follow the targets very well, I may ask him or her to count the targets as they go by or to pick a target and follow it all the way across.
OPK nystagmus with slow phase velocities of less than 80% of target velocity is generally considered abnormal. The response may be abnormal for one or both directions of target motion.
Charles Stockwell
Bio:
Charles W. Stockwell, Ph.D., earned his doctorate in psychology at the University of Illinois in 1968. Currently president of Charles W. Stockwell & Associates, a consulting firm he established in 1990, Dr. Stockwell's professional career spans academia and clinical practice. From 1986 to 1996, he was director of the vestibular laboratory at Providence Hospital in Southfield, Michigan. Prior to that, Dr. Stockwell was a professor in the departments of otolaryngology and audiology at Wayne State University, in Detroit. And, from 1972 through 1884, he advanced from assistant professor to professor in the departments of otolaryngology and communication at Ohio State University. Dr. Stockwell has authored two books, Manual of Electronystagmography and ENG Workbook, and contributed chapters to numerous others. He has published more than 40 papers in peer-reviewed journals and conference proceedings and has made more than 120 presentations at scientific meetings or continuing medical education courses.